When working with high voltages, the following precautions should be observed:

Access being locked and allowing only authorized personnel to enter is a crucial safety measure when working with high voltages. This precaution ensures that only those who are trained and equipped to handle potentially dangerous situations have access to the area where high-voltage work is being performed. This helps minimize the risk of accidental exposure to high voltage conditions, as unauthorized or untrained individuals may not be aware of the hazards and might inadvertently create dangerous situations for themselves or others.

Locking access also serves to prevent unauthorized equipment tampering or interference, which can pose serious safety risks. By restricting access to only qualified personnel, organizations can better manage safety protocols and ensure compliance with regulatory standards related to electrical safety, reducing the likelihood of accidents and electrical hazards.

The other options are relevant to safety but may not adequately address comprehensive safety management or could be misapplied. For example, ensuring voltage safety is important, but it does not account for the necessity of controlled access. The involvement of utility workers is specific but doesn't guarantee safety unless full training and access control are enforced. Finally, grounding straps should generally remain in place to ensure safety during high-voltage work, highlighting the importance of maintaining safe practices throughout.